System and method of article feeder operation

ABSTRACT

Embodiments of a system and method for shingulating, singulating, and synchronizing articles in an article feeder system are disclosed. The article feeder system may include a shingulating device configured to receive a stack of articles and to produce a positively lapped stack of articles, a plurality of picking devices configured to pick one or more articles from the positively lapped stack of articles and to produce one or more singulated articles, and one or more synchronization devices configured to deliver the one or more singulated articles to one or more sorter windows.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57. Thisapplication is a continuation of U.S. application Ser. No. 15/989,039,filed May 24, 2018, which is a continuation of U.S. application Ser. No.14/742,480, filed Jun. 17, 2015, now U.S. Pat. No. 10,287,107, which isa continuation of U.S. application Ser. No. 13/827,122, filed Mar. 14,2013, now U.S. Pat. No. 9,061,849, which are hereby incorporated byreference in their entirety.

BACKGROUND OF THE DEVELOPMENT Field of the Development

The disclosure relates to the field of automatic feeding and sorting ofitems. More specifically, the present disclosure relates to theautomatic shingulation, singulation, and sorting of articles from a bulkstack of articles.

Description of the Related Art

Articles, such as items of mail, are frequently provided in bulk andmust be sorted into individual articles or items for processing orrouting. Sorting these articles into individual articles, orsingulation, may be done automatically by placing a bulk stack ofarticles into an article feeder. The singulated articles may then besorted into various sorter windows. Sorters operate at high speeds andproduce available sorter windows for insertion of articles at a highrate. An article feeder may not properly sort the articles into thevarious sorter windows if the article feeder operation and the sorterare not synchronized with one another. Furthermore, damage to thearticles and selection of more than one article in the singulationprocess, or double feeding, may occur if the article feeder is notconfigured to operate at a high rate. Accordingly, systems and methodsare needed for automatic shingulation, singulation, and sorting ofarticles from a bulk stack of articles to maximize article feed rate andminimize damage and double feeding.

SUMMARY

Some embodiments disclosed herein relate to an article feeder system.The article feeder system may include a shingulating device configuredto receive a stack of articles and to produce a positively lapped stackof articles, a plurality of picking devices configured to pick one ormore articles from the positively lapped stack of articles and toproduce one or more singulated articles, and one or more synchronizationdevices configured to deliver the one or more singulated articles to oneor more sorter windows.

In some embodiments, the shingulating device comprises a bottomtransport belt having a transport surface extending in a firstdirection; a shearing device; and a perforated belt having a surfaceextending in a second direction different than the first direction, theperforated belt being adjacent to the bottom transport belt, wherein thebottom transport belt and the perforated belt are configured to move thestack of articles toward the shearing device, and wherein the shearingdevice is configured to apply a shearing force on a portion of the stackof articles to produce the positively lapped stack of articles. In someembodiments, the article feeder system may include a vacuum systemconfigured to apply suction through one or more openings in theperforated belt.

In some embodiments, the shingulating device comprises a plurality ofbottom transport belts, each bottom transport belt having a transportsurface extending in a first direction; a shearing device; and aplurality of perforated belts, each perforated belt having a surfaceextending in a second direction different than the first direction andbeing adjacent to at least one of the plurality of bottom transportbelts, wherein at least one of the plurality of bottom transport beltsand at least one of the plurality of perforated belts are configured tomove the stack of articles toward the shearing device, and wherein theshearing device is configured to apply a shearing force on a portion ofthe stack of articles to produce the positively lapped stack ofarticles.

In some embodiments, the each of the plurality of picking devicescomprises a vertically oriented perforated belt having one or moreopenings in its surface, the perforated belt configured to be driven bya motor; a vacuum manifold adjacent to the perforate belt; a vacuum unitconfigured to apply suction through the vacuum manifold, wherein thevacuum manifold is configured to apply the suction through the one ormore openings in the surface of the perforated belt; and a vacuum valveconfigured to control the amount of suction applied by the vacuum unitto the vacuum manifold. In some embodiments, each of the plurality ofpicking devices is configured to pick an article from the positivelylapped stack of articles, including opening the vacuum valve andexposing the vacuum manifold to the suction from the vacuum unit, thevacuum manifold applying the suction through the one or more openings inthe perforated belt to attach the article to the perforated belt; andproduce a singulated article, including separating the article from thepositively lapped stack of articles by driving the perforated belt withthe attached article forward using the motor.

In some embodiments, the plurality of picking devices are configured ina row, wherein a downstream most picking device in the row that issubstantially completely covered by the positively lapped stack ofarticles is configured to pick the article from the positively lappedstack of articles and to produce the singulated article.

In some embodiments, each of the plurality of picking devices is locatedin a respective picking zone, each respective picking zone including apicking device and an anti-doubling device opposite the picking device,the anti-doubling device configured to prevent more than one article ata time from being picked from the positively lapped stack of articles.In some embodiments, the anti-doubling device includes a presence sensorconfigured to detect a first article; an edge detector sensor positionedupstream from the presence sensor and configured to detect an edge of asecond article; and a vacuum unit configured to apply suction to thesecond article when the presence sensor detects the first article duringa time period in which the edge detector detects the edge of the secondarticle. In some embodiments, the presence sensor includes aphotoelectric sensor. In some embodiments, the perforated belt is drivenby a single servo motor.

In some embodiments, the one or more synchronization devices includes agroup of paired pinch wheels driven at a variable speed by a pinch wheelmotor.

In some embodiments, the article feeder system further comprises acontroller configured to control movement of each article of the stackof articles to synchronize a first time when each of the one or moresingulated articles reaches an exit point with a second time when asorter window reaches the exit point. In some embodiments, thesynchronization of the first time with the second time is based on oneor more of a location of a first article being picked by a first pickingdevice, a velocity of the first article, a location of the sorterwindow, a velocity of the sorter window, an acceleration rate of each ofa plurality perforated belts included in each of the plurality ofpicking devices, an acceleration rate of the one or more synchronizationdevices, a maximum velocity allowed for each of the plurality perforatedbelts included in each of the plurality of picking devices, a maximumvelocity allowed for a perforated belt included in the shingulatingdevice, a maximum velocity allowed for the one or more synchronizationdevices, a length of each of the plurality of perforated belts includedin each of the plurality of picking devices, a length of the perforatedbelt included in the shingulating device, a number of perforated belts,a length of the one or more synchronization devices, and a number of theone or more synchronization devices.

Some embodiments disclosed herein relate to a method of managingarticles in an article feeder. The method comprises receiving a stack ofarticles at a shingulating device and producing a positively lappedstack of articles; picking one or more articles from the positivelylapped stack of articles using one or more picking devices and producingone or more singulated articles; and delivering the one or moresingulated articles to one or more sorter windows using one or moresynchronization devices.

In some embodiments, producing the positively lapped stack of articlescomprises moving the stack of articles toward a shearing device using abottom transport belt and a perforated belt of the shingulating device,the bottom transport belt having a transport surface extending in afirst direction and the perforated belt having a surface extending in asecond direction different than the first direction; and applying ashearing force on the stack of articles using the shearing device.

In some embodiments, the method further comprises applying suctionthrough one or more openings in the perforated belt using a vacuumsystem.

In some embodiments, picking the one or more articles from thepositively lapped stack of articles comprises opening a vacuum valve ofa first picking device to expose a vacuum manifold of the first pickingdevice to suction from a vacuum unit; applying the suction from thevacuum manifold through one or more openings in a perforated belt of thefirst picking device to one of the one or more articles; and attachingthe article to the perforated belt using the suction through the one ormore openings. In some embodiments, producing the one or more singulatedarticles comprises separating an article from the positively lappedstack of articles by driving the perforated belt with the attachedarticle forward using a motor. In some embodiments, the singulatedarticle is picked and produced by a downstream most picking device in arow of picking devices that is substantially completely covered by thepositively lapped stack of articles.

In some embodiments, the method further comprises preventing more thanone article at a time from being picked from the positively lapped stackof articles using an anti-doubling device located in a respectivepicking zone, each respective picking zone including a respectivepicking device. In some embodiments, the method further comprisesdetecting a first article using a presence sensor of the anti-doublingdevice; detecting an edge of a second article using an edge detectorsensor of the anti-doubling device, the edge detector sensor beingpositioned upstream from the presence sensor; and applying suction tothe second article using the vacuum unit when the presence sensordetects the first article during a time period in which the edgedetector detects the edge of the second article.

In some embodiments, the method further comprises controlling movementof each article of the stack of articles to synchronize a first timewhen each of the one or more singulated articles reaches an exit pointwith a second time when a sorter window reaches the exit point. In someembodiments, synchronization of the first time with the second time isbased on one or more of a location of a first article being picked by afirst picking device, a velocity of the first article, a location of thesorter window, a velocity of the sorter window, an acceleration rate ofeach of a plurality perforated belts included in each of the pluralityof picking devices, an acceleration rate of the one or moresynchronization devices, a maximum velocity allowed for each of theplurality perforated belts included in each of the plurality of pickingdevices, a maximum velocity allowed for a perforated belt included inthe shingulating device, a maximum velocity allowed for the one or moresynchronization devices, a length of each of the plurality of perforatedbelts included in each of the plurality of picking devices, a length ofthe perforated belt included in the shingulating device, a number ofperforated belts, a length of the one or more synchronization devices,and a number of the one or more synchronization devices.

Some embodiments disclosed herein relate to an article feeder systemcomprising means for receiving a stack of articles to produce apositively lapped stack of articles; means for picking an article fromthe positively lapped stack of articles to produce one or moresingulated articles; and means for delivering the singulated article toa sorter window.

Some embodiments disclosed herein relate to an article feeder systemcomprising a plurality of picking devices, at least one of the pluralityof picking devices configured to receive a stack of articles and producea positively lapped stack of articles; pick one or more articles fromthe positively lapped stack of articles and produce one or moresingulated articles; and deliver the one or more singulated articles toone or more sorter windows.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the disclosure will become morefully apparent from the following description and appended claims, takenin conjunction with the accompanying drawings. Understanding that thesedrawings depict only several embodiments in accordance with thedisclosure and are not to be considered as limiting of its scope, thedisclosure will be described with additional specificity and detailthrough use of the accompanying drawings.

FIG. 1 is a perspective view of one embodiment of an article feedersystem.

FIG. 2 illustrates a perspective view of an exemplary stack of articles.

FIG. 3 illustrates a top plan view of an example of a shingulated stackof articles with one or more positively lapped articles.

FIG. 4 is a perspective view of one embodiment of a shingulating device.

FIG. 5A is a perspective view of another embodiment of a shingulatingdevice.

FIG. 5B is a side plan view taken along line 5B-5B of FIG. 5A, andillustrating another embodiment of a shingulating device.

FIG. 6A is a perspective view of one embodiment of an article feedersystem including picking devices and anti-doubling devices.

FIG. 6B is an enlarged portion of a picking device as indicated by thedashed line 6B of FIG. 6A.

FIG. 7A is a perspective view of one embodiment of an article feedersystem including a group of picking zones.

FIG. 7B is a side plan view taken along line 7B-7B of FIG. 7A, andillustrating an example of detecting a shingulated stack of articles oran attached group of articles approaching a picking zone.

FIG. 8 is a perspective view of one embodiment of a synchronizationdevice.

FIG. 9A is a top plan view of an article feeder system with a floatingpick point.

FIG. 9B is a top plan view illustrating an exemplary article feedersystem operating using virtual windows.

FIG. 9C is a top plan view of a pulley system for driving a perforatedbelt of a picking device.

FIG. 9D is a perspective view of a perforated timing belt.

FIG. 10 is a side plan view of an article feeder system using virtualwindows for synchronization of an article with a sorting window.

FIG. 11A is a schematic diagram illustrating an example of a method ofcontrolling a virtual axis.

FIG. 11B is a side plan view of an article feeder system andillustrating an example of a method of synchronizing an article with asorter window using a pick zone operation.

FIG. 11C is a side plan view of an article feeder system andillustrating an example of a method of coordinating the operation ofpicking zones with master and slave axes to control the picking of anarticle.

FIG. 12A is a side plan view of an article feeder system includingpicking zones and sensors.

FIG. 12B is a side plan view of an article feeder system andillustrating an example of a method of variably controlling picking zonevacuum systems based on the sensor feedback.

FIG. 13 is a side plan view of an article feeder system using a pickzone operation for correction control.

FIG. 14 is a flow chart depicting one embodiment of a method of managingarticles in an article feeder.

FIG. 15 is a flow chart depicting one embodiment of a method ofdetermining a velocity or movement profile.

DETAILED DESCRIPTION OF EMBODIMENTS

In the following detailed description, reference is made to theaccompanying Figures, which form a part hereof. In the drawings, similarsymbols typically identify similar components, unless context dictatesotherwise. Thus, in some embodiments, part numbers may be used forsimilar components in multiple figures, or part numbers may vary fromfigure to figure. The illustrative embodiments described in the detaileddescription, drawings, and claims are not meant to be limiting. Otherembodiments may be utilized, and other changes may be made, withoutdeparting from the spirit or scope of the subject matter presented here.It will be readily understood that the aspects of the presentdisclosure, as generally described herein, and illustrated in theFigures, can be arranged, substituted, combined, and designed in a widevariety of different configurations, all of which are explicitlycontemplated and made part of this disclosure.

The systems and methods described herein provide for faster and moreefficient shingulation, singulation, and sorting of articles. As usedherein, the term shingulation may refer to the process of extruding astack of articles to produce a positively lapped stack of articles. Asused herein, positive lapped or positive lapping may refer to theorganization of the position of the leading edges of the articles of thestack. Details relating to shingulation and positive lapping will bedescribed further below with respect to FIG. 2-4. As used herein, theterm singulation refers to picking articles from the positively lappedshingulated stack to produce individual articles. The articles describedherein may include, for example, articles of mail, magazines, catalogs,and the like. Although the present disclosure describes systems,methods, and devices for shingulating, singulating, and/or sortingarticles of mail, catalogs, and magazines, it will be apparent to one ofskill in the art that the disclosure presented herein is not limitedthereto. For example, the development described herein may haveapplication in a variety of manufacturing, assembly, or sortingapplications.

These articles or flats may be processed as a stack. As used herein, theterm stack may refer to a single article or to one or more articlesgrouped together. These articles may be singulated into individualarticles for processing or routing, which may be done automatically byplacing the stack of articles into an article feeder that may route thearticles to various sorter windows. Sorters operate at high speeds andpresent available sorter windows for insertion of the articles at a highrate. Errors may occur if the article feeder operation and the sorterare not synchronized with one another. For example, the article feedermay not properly sort the articles into the various sorter windows ormay miss the windows completely. Furthermore, damage to the articlesand/or selection of more than one article in the singulation process, ordouble feeding, may occur if the article feeder is not properlyconfigured to operate at a high rate. Accordingly, systems and methodsare described for automatic shingulation, singulation, and sorting ofarticles from a bulk stack of articles including synchronization ofarticle feeder operation. For example, articles from a bulk stack ofarticles may be singulated, and the movement of the singulatedindividual articles may be synchronized such that they can be deliveredinto individual cells of a moving sorter.

FIG. 1 depicts an embodiment of an article feeder system 102. Thearticle feeder system 102 comprises a frame 120, conveyor 104, avertically oriented wall 106, a shingulating device 108, a group ofpicking devices 110, an anti-doubling device 112, one or more rollers118, and a synchronization device 114. The article feeder system 102 hasa first end 122 and a second end 124. The frame 120 provides support forthe conveyor 104, the wall 106, the shingulating device 108, the groupof picking devices 110, the anti-doubling device 112, the one or morerollers 118, and the synchronization device 114. The frame 120 isgenerally table shaped, being elevated off the ground by a plurality oflegs (not shown) or by any other means known in the art.

The conveyor 104 is located in proximity to the first end 122 of thearticle feeder system 102. The conveyor 104 may include a generallyhorizontal flat surface and is sized and shaped to support a stack ofarticles. In some embodiments, the conveyor 104 may include an angledsurface that is sized and shaped to support the stack of articles. Thevertically oriented wall 106 is located adjacent to one side of theconveyor 104. In some embodiments, the wall 106 may be disposed at aright angle relative to the conveyor 104. In some embodiments, the wall106 may be angled at any suitable angle relative to the conveyor 104.The conveyor 104 is configured to move in a direction 126 toward theshingulating device 108. The shingulating device 108 is located inproximity to the first end 122 of the article feeder system 102 adjacentto the conveyor 104. The shingulating device 108 is arranged generallyperpendicularly relative to the conveyor 104. Different embodiments ofthe shingulating device 108 will be described in further detail below.

The one or more rollers 118, the picking devices 110, and theanti-doubling devices 112 are located downstream from the shingulatingdevice 108. As used herein, the term downstream may refer to a directionfrom the first end 122 to the second end 124. Various sensors may alsobe located in proximity to the anti-doubling devices, which will bedescribed in further detail below. The picking devices, theanti-doubling devices, the sensors, and/or the rollers 118 may becollectively referred to herein as a picking zone. The one or morerollers 118 may be located adjacent to the first two picking devices110. The anti-doubling devices 112 may be located downstream from therollers 118 and may be adjacent to the remaining three picking devices110. While five picking devices are illustrated in FIG. 1, a person ofskill in the art will recognize that any other number of picking devicesmay be included as part of the article feeder system 102. Differentembodiments of the picking zones will be described in further detailbelow.

The synchronization device 114 is located downstream from the pickingdevices 110. The synchronization device 114 includes one or more pairedpinch wheels. The synchronization device 114 will be described infurther detail below.

FIG. 2 illustrates an example of a stack of articles 202. Each articleof the stack 202 includes a front side, a back side, two lateral sides,a top, and a bottom. The stack of articles 202 may be placed on theconveyor 104 with the bottom of each article making contact with theconveyor 104 and the front side of each article positioned to move inthe direction of the arrows illustrated in FIGS. 1 and 2. Each articleof the stack 202 includes a binding 204 along the bottom of each articlethat is aligned substantially parallel to the conveyor 104. The frontside of each article is aligned substantially parallel to each of theother articles in the stack 202, and the front side of each article isaligned to face in the same direction. The front and back sides of eacharticle are aligned to be substantially perpendicular to the conveyor104. In some embodiments, the stack of articles 202 may be angledrelative to the conveyor 104 at any suitable angle. For example, thestack 202 may be positioned at an angle of 0 to 10 degrees relative tothe conveyor. The articles of the stack 202 are also aligned front toback, with each article touching and supporting a neighboring article inthe stack 202. One of the lateral sides of the stack of articles 202 maybe aligned against the vertically oriented wall 106, which may bepositioned substantially perpendicularly to the front and back sides ofthe stack 202.

In some embodiments, the article feeder system 102 may include a supportstructure or arm that may provide support for the stack of articles 202.For example, a support structure or arm may be positioned substantiallyparallel to and may make contact with the back side of the stack ofarticles 202. The support structure or arm may move along the conveyor104 along with the stack 202 to provide support as the stack 202 movescloser to the shingulating device 108.

The different components of the article feeder system 102 are used toshingulate, singulate, and synchronize the stack of articles 202. Theshingulating device 108 is configured to shingulate the stack ofarticles 202. As used herein, the term shingulation may refer to theprocess of extruding the stack 202 to produce a positively lapped stackof articles traveling toward the group of picking devices 110. Thepicking devices 110 may also be referred to as singulating devices 110.As used herein, positive lapping may refer to the organization of theposition of the leading edges of the articles of the stack 202. Forexample, FIG. 3 illustrates a shingulated stack of articles 302 with oneor more positively lapped articles 304, including the leading edge ofeach article being positioned downstream relative to the leading edge ofan adjacent article. As the articles of the stack 202 travel toward theshingulating device 108 in direction 306, the articles are shingulatedby the shingulating device 108 to produce the positively lapped stack ofarticles 302. After being shingulated, the positively lapped stack ofarticles 302 travel in direction 308 toward the group of picking devices110.

FIG. 4 illustrates an example of a shingulating device 108. As theconveyor 104 moves, the stack of articles of 202 travels along theconveyor 104 in the direction 126 toward the shingulating device 108. Asnoted above, a support structure or arm may provide support for thestack of articles 202 as the stack 202 travels along the conveyor 104.The shingulating device 108 receives the stack of articles 202 andoperates to shingulate the articles to produce the positively lappedstack of articles 302.

The shingulating device 108 includes a bottom transport belt 404, ashearing device 408, and a perforated belt 406. The bottom transportbelt 440 has a transport surface extending in a first direction. Thefirst direction may be a substantially horizontal direction. The bottomtransport belt 404 is configured to be moved in a downstream directiontoward the shearing device 408 using one or more belt drives 410. Insome embodiments, the shearing device 408 is spring loaded. Theperforated belt 406 includes one or more openings. In some embodiments,the one or more openings include a plurality of small holes distributedgenerally uniformly over the surface of the perforated belt 406. In someembodiments, the one or more openings include one or more elongate holesarranged in lines parallel or perpendicular to the length of theperforated belt 406. In some embodiments the openings may have othersuitable shapes. The openings may be concentrated in one region or areaof the perforated belt 406 or may be uniformly distributed over thesurface of the perforated belt 406. The perforated belt 406 furtherincludes a surface extending in a second direction different than thefirst direction. The second direction may be a substantially verticaldirection relative to the bottom transport belt 404. For example, theperforated belt 406 may be at a right angle relative to the generallyhorizontal direction of the bottom transport belt 404. The perforatedbelt 406 is adjacent to the bottom transport belt 404 and is configuredto be moved in the downstream direction toward the shearing device 408using one or more belt drives 410.

The shingulating device 108 further includes a vacuum system (notshown). The vacuum system may include a vacuum unit, a vacuum manifold,and/or a vacuum valve. The vacuum system is configured to apply suctionthrough the one or more openings in the perforated belt 406 forattaching one or more articles thereto by opening the vacuum valve andexposing the vacuum manifold to a vacuum force originating from thevacuum unit. The vacuum force may pull one or more articles of the stack202 through the one or more openings of the perforated belt 406 toeffectively connect the article to the perforated belt 406. As the oneor more articles of the stack 202 impinges on the surface of theperforated belt 406, the vacuum valve may expose the vacuum manifold tothe vacuum force (if not already applied) and the one or more articlesis held to the surface of the perforated belt 406 by the vacuum forcethrough the one or more holes in the perforated belt 406. The one ormore articles, held against the perforated belt 406, is thus moved inthe direction of movement of the perforated belt 406.

The bottom transport belt 404 and the perforated belt 406 are configuredto move the stack of articles 202 in the downstream direction toward theshearing device 408, and the shearing device 408 is configured to applya shearing force on a portion of the stack of articles to produce thepositively lapped stack of articles 302. The stack of articles 202 restson the bottom belt 404 and is also coupled to the perforated belt 406via the suction provided through the one or more openings. For example,the articles are held to the surface of the perforated belt 404 by avacuum force exerted on the article through the one or more openings inthe perforated belt 404, as described above. The stack of articles 202,being held against the perforated belt 404 and resting on the bottomtransport belt 404 are thus moved in the downstream direction. As thesebelts are moved forward in the downstream direction, the stack 202 ispressed against the shearing device 408, which imparts a shearing forceon the stack of articles 202. For example, the shearing device 408 mayimpart a shearing force on the stack of articles 202 by applyingconstant pressure on the stack 202 and forcing only a portion of thestack 202 at a time to enter the first pick point 412. In someembodiments, the shearing device 408 is spring loaded and may impart theshearing force using a spring to apply pressure to the stack of articles202. By imparting the shearing force on the stack of articles 202, theshearing device 408 effectively extrudes and creates a positive lappedconfiguration of the stack of articles 202, resulting in the positivelylapped shingulated stack of articles 302.

The shingulating device 108 may be configured to deliver the stack ofarticles in a positively lapped configuration at a system rate to afirst pick point 412, which is the point at which the articles begintransition from being shingulated to being singulated. In someembodiments, the bottom transport belt 404 and the perforated belt 406may move at a slower, more continuous speed relative to the belts of thepicking devices 110, which will be described below. In some embodiments,the shingulating belts may not start and stop with each picked article.In some embodiments, bottom transport belt 404 and the perforated belt406 of the shingulating device 108 may automatically turn off when noarticles are within a certain distance from the belts. When the stack ofarticles 202 makes contact with or is within a certain distance from thebottom transport belt 404 and/or the perforated belt 406, the belts mayautomatically turn on in preparation for the shingulation of the stack202. The stack of articles 202 may be sensed by a sensor, such as aninfrared or optical photo-eye or proximity sensor.

FIG. 5A illustrates another example of a shingulating device 108. Theshingulating device 108 includes bottom transport belts 504 and 506.Each transport belt 504 and 506 has a transport surface extending in afirst direction, such as a substantially horizontal direction. Theshingulating device 108 further includes a plurality of perforated belts508, each of the perforated belts including one or more openings,similar to the one or more openings described above with respect to theperforated belt 406. Each of the perforated belts 508 has a surfaceextending in a second direction that is different than the firstdirection. The second direction may be a substantially verticaldirection relative to the bottom transport belts 504 and 506. Forexample, perforated belts 508 may be at a right angle relative to thegenerally horizontal direction of the transport belts 504 and 506. Theplurality of perforated belts 508 are adjacent to at least one of theplurality of bottom transport belts 504 and 506. The shingulating device108 further includes a shearing device 510 that is used to impart ashearing force on the stack of articles 202. As the conveyor 104 movesforward, the stack of articles 202 rests on the bottom belts 504 and 506and is also coupled to each of the perforated belts 508 via suctionprovided through the one or more openings of each perforated belt. Asthe bottom transport belt 504 and the first two perforated belts aremoved forward, the stack 202 is pressed against the shearing device 510for creating a positive lapped configuration of the stack of articles202.

FIG. 5B illustrates another embodiment of a shingulating device 108,illustrating a side elevation view taken along line 5B-5B of FIG. 5A.Shingulating device 108 includes a perforated belt 508A located in ashingler zone and a perforated belt 508B located in an intermediatezone. The bottom transport belt 504 illustrated in FIG. 5A may belocated in the shingle zone along with the perforated belt 508A. Thebottom transport belt 506 illustrated in FIG. 5A may be located in theintermediate zone along with the perforated belt 508B. In someembodiments, the bottom transport belt 504, the perforated belt 508A,and/or the corresponding vacuum(s) may automatically turn off when noarticles are within a certain distance from the belts. When the stack ofarticles 202 makes contact with or is within a certain distance from thebottom transport belt 504 and/or the perforated belt 508A, the belts andvacuum(s) may automatically turn on in preparation for the shingulationof the stack of articles 202. The stack of articles 202 may be sensed bya sensor, such as an infrared or optical photo-eye or proximity sensor,located at a point at the beginning of the bottom transport belt 504and/or the perforated belt 508A.

In some embodiments, the bottom transport belt 504, the perforated belt508A, and the corresponding vacuums may be variably controlled in orderto control the flow of articles to the perforated belt 508B and thebottom transport belt 506. For example, the bottom transport belt 504and/or the perforated belt 508A may be started or stopped, or the speedof the belts 504 and/or 508A may be increased or decreased, at a firsttime depending on the number of articles that are located in theintermediate zone at the first time. For example, a thickness sensor 514may determine the thickness of the stack of articles in the intermediatezone. For example, the thickness sensor 514 may be a scale, a load cell,a force sensor, a strain gauge, or any other known sensor capable ofdetecting a force or weight and outputting an electrical signal. Inresponse, the bottom transport belt 504 and/or the perforated belt 508Amay be controlled (e.g., started, stopped, slowed down, sped up, etc.)based on the sensed thickness. For example, if the thickness sensor 514indicates that too many articles are located in the intermediate zone asdetermined by a thickness threshold, the bottom transport belt 504, theperforated belt 508A, and/or the corresponding vacuum(s) may be stoppedso that the bottom transport belt 506 and the perforated belt 508B inthe intermediate zone can reduce the amount of articles in theintermediate zone by passing the articles to the picking devices 512 and516. After the amount of articles is reduced below the threshold level,the belts 504 and 508A and the vacuum(s) may be started again. In someembodiments, a sensor 518 may be located at the first picking device 512and may be used to determine the speed at which to operate the bottomtransport belt 504 and/or the perforated belt 508A. For example, if noarticles are sensed by the sensor 518, the speed of the bottom transportbelt 504 and/or the perforated belt 508A may be increased until anarticle is sensed. The sensor 518 may be configured to detect theleading edge of an article and may include any suitable sensor, such asan infrared or optical photo-eye or proximity sensor.

In some embodiments, the bottom transport belt 506, the perforated belt508B, and the corresponding vacuum(s) may be variably controlled inorder to control the flow of articles to the picking devices 512 and/or516. For example, if no articles are sensed by the sensor 518,indicating that no articles are located at the first picking device 512,the bottom transport belt 506 and/or the perforated belt 508B may bestarted and/or sped up. If one or more articles are sensed by the sensor518, the intermediate perforated belt 508B may be stopped or may beslowed down until the sensor is clear. The vacuum(s) may be started orstopped with the belts in response to the results of the sensor 518.

In some embodiments, the sensor 518 may be configured to count thenumber of articles that are detected. The bottom transport belt 506, theperforated belt 508B, and/or the corresponding vacuum(s) may be variablycontrolled according to the number of sensed articles. In some aspects,a controller, processor, and/or memory may be coupled to the sensor 518and may be used to count the number of articles that are detected orsensed by the sensor 518. For example, if the sensor 518 indicates thatone article has been detected, an intermediate zone vacuum (not shown)may be turned on as well as the bottom transport belt 506 and theperforated belt 508B. Similarly, if the sensor 518 indicates that noarticles are detected, the intermediate zone vacuum and the belts 506and 508B may be turned on. On the other hand, for example, if the sensor518 indicates that two or more articles are detected, the intermediatezone vacuum may be turned off and the bottom transport belt 506 and theperforated belt 508B may be stopped. The controller or processor may beimplemented with any combination of general-purpose microprocessors,microcontrollers, digital signal processors (DSPs), field programmablegate array (FPGAs), programmable logic devices (PLDs), controllers,state machines, gated logic, discrete hardware components, dedicatedhardware finite state machines, or any other suitable entities that canperform calculations or other manipulations of information. The memorymay include a Random Access Memory (RAM) circuit, an ElectricallyErasable Programmable Read Only Memory (EEPROM), an ElectricalProgrammable Read Only Memory (EPROM), a Read Only Memory (ROM), anApplication Specific Integrated Circuit (ASIC), a magnetic disk, anoptical disk, and/or other types of memory well known in the art.

As a result of the variably controlled belts and vacuum(s), theshingulating device 108 may be configured to deliver the stack ofarticles in a positively lapped configuration at a system rate to afirst picking device 512, which is the point at which the articles begintransition from being shingulated to being singulated.

Returning to FIG. 1, each of the picking devices 110 is configured tosingulate one or more of the articles from the shingulated stack ofarticles 302. As used herein, the term singulation refers to pickingarticles from the positively lapped shingulated stack 302 to produceindividual articles. One or more of the picking devices 110 may includea roller 118 or an anti-doubling device 112. The rollers 118 may ensurethat the stack of articles stay in a stacked configuration and do notsag as they are transported along the article feeder system 102. FIG. 6Aillustrates another example of an article feeder system 102 includingpicking devices 110 and anti-doubling devices 112. The anti-doublingdevices 112 include edge detector sensors 610 and presence sensors 612.Details regarding the anti-doubling devices 112, edge detector sensors610, and presence sensors 612 will be discussed below with respect toFIGS. 7A and 7B.

FIG. 6B illustrates an enlarged portion of a picking device 110 asindicated by the dashed line 6B of FIG. 6A. The picking device 110includes a perforated belt 606, a perforated belt drive pulley 614, avacuum manifold 608 located adjacent to the perforated belt 606, avacuum unit 617, and a vacuum valve 616. A bottom transport belt 604 maybe included in the article feeder system 102 located adjacent to thepicking device 110 to support the articles as they move along thearticle feeder system 102. In some embodiments, the bottom transportbelt 604 may be the same bottom transport belt 404 illustrated in FIG. 4extending the length of the article feeder system. In some embodiment,the article feeder system 102 does not include the bottom transport belt604 located adjacent to the picking device 110 so that only theperforated belt 606 is included to transport articles in a downstreamdirection. In some embodiments, the picking devices 110 are configuredin a row, and a downstream most picking device in the row that issubstantially completely covered by the positively lapped stack ofarticles is configured to pick the article from the positively lappedstack of articles and to produce the singulated article. As used herein,substantially completely covered may refer to a picking device that hasa particular number of sensors blocked by one or more articles. Forexample, if each picking device includes four sensors (e.g.,photoelectric sensors, proximity sensors, infrared sensors, opticalsensors, and the like), and three of the four sensors are blocked by oneor more articles, that picking zone may be considered substantiallycompletely covered. As another example, a picking device issubstantially completely covered if all sensors for that picking deviceare blocked by one or more articles.

The perforated belt 606 may be vertically oriented and may have one ormore openings in its surface through which a vacuum source may beapplied. As used herein, vertically oriented may refer to asubstantially vertical angle. For example, vertically oriented may referto a right angle relative to the frame 120. As another example,vertically oriented may refer to any other suitable angle relative tothe frame 120, such as an angle anywhere from 50-60° (e.g., 50° , 60° ,70° , 80°). The perforated belt 606 is moved or driven using theperforated belt drive pulley 614. The perforated belt drive pulley 614may be driven by a motor, such as a single servo motor. The vacuum unit617 may be configured to apply a suction force through the vacuummanifold 608 and the vacuum manifold 608 may be configured to apply thesuction through the one or more openings in the surface of theperforated belt 606. The vacuum valve 616 may be configured to controlthe amount of suction applied by the vacuum unit 617 to the vacuummanifold 608.

The singulation, or picking, may be accomplished as the stack 302 movestoward the perforated belt 606 by opening the vacuum valve 616 andexposing the vacuum manifold 608 to a vacuum force. The vacuum force maypull a leading article 310 of the stack 302 through the one or moreopenings of the perforated belt 606 to effectively connect the article310 to the perforated belt 606. The leading article 310 is the articlein the stack 302 located closest to the perforated belt 606.Accordingly, as the leading article 310 of the stack 302 impinges on thesurface of the perforated belt 606, the vacuum valve 616 may expose thevacuum manifold 608 to the vacuum force (if not already applied). Theleading article 310 is held to the surface of the perforated belt 606 bythe vacuum force exerted on the leading article 310 through the one ormore holes in the perforated belt 606. The leading article 310, heldagainst the perforated belt 606, is thus moved in the direction ofmovement of the perforated belt 606 using the perforated belt drivepulley 614, thereby separating the individual article 310 from theshingulated positively lapped stack 302. As a result, the belt and theattached article 310 are driven forward of the shingulated stack 302,effectively singulating the article 310.

Multiple picking devices may be used, each including a perforated belt,a perforated belt drive pulley, a vacuum manifold, a vacuum valve, and avacuum unit. For example, five picking devices may be used to singulatethe stack of articles 302. A person of skill in the art will recognizethat any other number of picking devices may be used to accomplish thepurpose of singulating the stack 302.

The picking devices allow individual articles to be singulated from thestack 302 while also exposing the singulated article stream toanti-doubling devices 112. The anti-doubling devices 112 help to ensurethe fidelity of the singulated article stream. For example, articles maystick together for various reasons when picked by one of the pickingdevices, and attaching only one side of the article to the perforatedbelt may not prevent another article from sticking to the other side ofthe attached article opposite the perforated belt 606. In the event thatone or more articles are simultaneously picked from the stack 202, ananti-doubling device 112 may be used to expose the article attached tothe other side of the desired article to a vacuum source. The vacuumsource applied to the attached article is used to separate the attachedarticle from the desired article.

FIG. 7A illustrates an example of an article feeder system 102 includinga group of picking zones 704. The picking zones 704 includeanti-doubling devices 112A and 112B and picking devices 110. Theanti-doubling devices 112A and 112B include edge detector sensors 610and presence sensors 612 (not shown in FIG. 7A), similar to edgedetector sensors 610 and presence sensors 612 illustrated in FIG. 6A.Each of the areas of the article feeder system 102 including a pickingdevice 110, an anti-doubling device 112A and 112B, an edge detectorsensor 610, and a presence sensor 612 may be referred to as a pickingzone. The edge detector sensor 610 may be positioned upstream from thepresence sensor 612 and may be configured to detect an edge of anarticle. In some embodiments, the presence sensor 612 includes aphotoelectric sensor or photo-sensor. Although a certain type of sensoris described herein, a person of skill in the art will recognize thatother suitable types of sensors may be used in various configurations toaccomplish the purpose of sensing the presence of an article.

Three anti-doubling devices 112A and 112B may be used to ensure that thepicking devices 110 properly singulate the articles from the stack 302.In some embodiments, some combination of the anti-doubling devices 112Aand/or 112B will have a low level of constant vacuum to encourage thearticles to be shingulated prior to being singulated by one of thepicking devices. For example, if the article feeder system 102 does notinclude a dedicated shingulating device 108, the first two anti-doublingdevices 112A may have a constant level of vacuum at all times in orderto effectively shingulate the stack of articles 202. As another example,even if a dedicated shingulating device 108 is included in the articlefeeder system 102, the picking zones may be used to re-shingulate thestack of articles in the event that the articles have shifted duringtransport. A particular level of constant vacuum pressure may bemeasured and used to ensure that the articles are not damaged as theyare shingulated.

In some embodiments, the first two anti-doubling devices 112A may betriggered by one or more edge detector sensors (not shown) that detectthe presence of a shingulated stack of articles or the presence of anarticle that is attached to a desired article to be singulated. When oneor more edge detectors indicate that a shingulated stack or an attachedarticle is located at the particular picking zone, an anti-doublingdevice 112A and/or 112B may be turned to a high vacuum level to attemptto hold back the other articles of the shingulated stack or the attachedarticle from the desired article that is to be singulated. FIG. 7Billustrates an example of an anti-doubling device 112 detecting ashingulated stack of articles or an attached group of articlesapproaching a picking zone. At time 1 (T1), a first article 702 crossesan edge detector sensor 610. In response, it is determined that an edgeis found. For example, a controller or processor may receive anindication that an edge is detected by the edge detector sensor 610. Thecontroller or processor may be implemented with any combination ofgeneral-purpose microprocessors, microcontrollers, digital signalprocessors (DSPs), field programmable gate array (FPGAs), programmablelogic devices (PLDs), controllers, state machines, gated logic, discretehardware components, dedicated hardware finite state machines, or anyother suitable entities that can perform calculations or othermanipulations of information. At T1, the presence sensor 612 is notblocked. Accordingly, it is determined that only a first edge has beendetected, indicating that only a single article is present in thepicking zone. As a result, the vacuum pressure is not increased to ahigh vacuum at T1.

At time 2 (T2), the first article 702 crosses the presence sensor 612. Asecond edge has not been reported by the edge detector sensor 610 at T2,thus the vacuum pressure is not increased at T2. At time 3 (T3), thesecond article 704 breaks the plane of the edge detector sensor 610,which reports the edge of the second article 704 to the controller orprocessor. At T3, the presence sensor 612 is also blocked by the firstarticle 702. As a result, it is determined that there is more than onearticle, one of which needs strong anti-doubling in order to properlysingulate the desired article. Accordingly, the anti-doubling device 112is turned on to full vacuum in order to separate any articles from thedesired article to be singulated by the picking zone. For example, inthe event more than one article is simultaneously separated from theshingulated stack 302, the anti-doubling device 112 may be turned tofull vacuum in order to separate the desired article from the otherarticles. As illustrated in FIG. 7B, the downstream edge 706 of theanti-doubling device 112 body is positioned just downstream from theedge detector sensor 610 so the sensor 610 is known to be acting only onthe second article 704.

Returning again to FIG. 1, the article feeder system 102 furtherincludes a synchronization device 114. FIG. 8 illustrates an example ofa synchronization device 114 that includes a group of paired pinchwheels 804. The synchronization device 114 may be located downstreamfrom the last picking zone 806. The pinch wheels 804 may be driven at avariable speed by one or more pinch wheel motors (not shown). A pinchwheel motor may include a servo motor or any other suitable motor fordriving the pinch wheels. While a certain number of pinch wheel pairs isillustrated in FIG. 8, a person of skill in the art will recognize thatany other number of pinch wheels may be used to accomplish the purposeof transferring articles from the article feeder system 102 to therendezvous point 116. The rendezvous point 116 may also be referred toherein as an exit point. The rendezvous point 116 is the point at whichan article leaves the article feeder system 102 for depositing into asorter window 117 of a sorter.

In some embodiments, synchronization of the various articles with thesorter windows may be accomplished by the synchronization device 114, aswell as by the picking zones as the articles are picked and transportedfrom picking zone to picking zone. In some embodiments, as describedfurther below, synchronization may be accomplished using only thepicking zones. For proper synchronization, the leading edge of anarticle should be delivered to the rendezvous point 116 at a line speedwithin a small timing window into the sorter. For example, the linespeed may be 3.15 m/s and the sorter window may be at +−15 msec. In someembodiments, once the article has been delivered to the rendezvous point116 within the timing window, the velocity of the article may remainconstant throughout the rest of the process as it is transported to andinducted into the sorting window of the sorter. Once the system issynchronized, the article and the sorter window are coupled with oneanother so that the article is accurately placed in the window.Synchronization of the articles and the sorter windows may allowaccurate processing of the articles at a desired rate. For example,synchronization may allow the articles to be processed at a rate of sixor more articles per second. A person of skill in the art will recognizethat other rates may be achieved using the article feeder system and thesynchronization process, as desired for the particular application.

The flow of the shingulated stack of articles should match the outputrate of the system in order to achieve proper synchronization.Controlling the feed rate of the shingulated stack of articles may bechallenging due to the positively lapped configuration of the articles,as illustrated in FIG. 3. This challenge is due to the fact that thefeed rate may be determined with the same method as that used for thesingulated articles, which uses the velocity of the article flow and thedistance between leading edges of the articles. In the case of thesingulated article stream, leading edges can be easily identified usingsensors (e.g., photoelectric sensors) because there are gaps betweeneach article. In the case of a shingulated stack of articles, gaps donot exist because the article is positively lapped. The amount ofarticle lapping determines the front to front spacing, and this lappingamount varies from moment to moment as the articles move downstream.

In order to overcome this control issue, the article feeder system 102may allow the pick point to float or vary. As used herein, the term pickpoint may refer to the point at which the positively lapped stack ofarticles 302 transitions from being shingulated to being singulated. Thepick point may be varied by allowing all picking devices 110 to act bothin a shingulation capacity and in a picking (singulation) andsynchronization capacity. In some embodiments, synchronization of thearticles with the sorter windows may be accomplished using only pickingdevices 110 and/or picking zones that perform shingulation, picking(singulation), and synchronization without the use of a shingulatingdevice or synchronization device. FIG. 9A illustrates an overhead viewof an article feeder system 102 that allows the pick point to float andthat allows continuous synchronization of the each article with adesired sorting window. In some embodiments, the article feeder system102 may not include a dedicated shingulating device 108 or a dedicatedsynchronization device 114 as in FIG. 1. In these embodiments, thepicking zones including the picking devices 110 and anti-doublingdevices 112 may be used to shingulate, pick, singulate, and synchronizethe articles as they are transported downstream along the article feedersystem 102. Accordingly, as an article is picked and singulated by apicking device, the shingulation feed-to point and the pick point willbe changed to that picking device and will thus float or vary. In someembodiments, as each article is picked and singulated from a moredownstream picking device than the previous article, the rate of theshingulating device may be retarded (e.g., the velocities of the bottomtransport belt and/or the perforated belt may be lowered). In someembodiments, when an article is picked from a more upstream pickingdevice than the previous article, the rate of shingulating device may beincreased. As a result, the pick point floats or varies based on wherethe previous article was picked. The nominal pick point may be locatedin a picking device that is located in the middle of the pickingdevices. Details regarding FIG. 9A will be discussed in more detailbelow.

A software program may be used to determine if an article being pickedcan be synchronized to the next available sorter window based on variouscriteria. The criteria that may be taken into account includes, but isnot limited to, the location of the current article being picked by apicking device, the current velocity of the article being picked, thelocation of the sorter window for which the article is beingsynchronized, the velocity of the sorter window, the design accelerationrate allowed for the perforated belts of the picking devices and/or theshingulating device, the design acceleration rate allowed for thesynchronization device, the maximum velocity allowed for the perforatedbelts of the picking devices and/or the shingulating device, and themaximum velocity allowed for the synchronization device. In someembodiments, the velocity of the sorter window may be constant. Otherconstraints may include the design geometries of the various componentsof the article feeder system, such as the length of the perforated beltsof the picking devices and/or the shingulating device, the number ofperforated belts, the length of the synchronization device, and thenumber of pinch wheels in the synchronization device. Trajectorycalculations may be used to ensure article synchronization with thesorter. For example, the following standard linear motion with uniformacceleration/deceleration equations may be used to determine if anarticle can be synchronized given various initial conditions:Distance=Velocity×Time  (Equation 1)Distance=Time×(Vfinal+Vinitial)/2  (Equation 2)Time=(Vfinal−Vinitial)/Acceleration  (Equation 3)

Equations 1-3 may be expanded as follows to develop a velocity ormovement profile for an article based on initial conditions of thearticle feeder system:Dw=Vw×Trp  (Equation 4)Dm=[Tap×{(Vfap+Viap)/2}]+[Tdp×{(Vfdp+Vidp)/2}]+[Tc×Vc]+[Tas×{(Vfas+Vias)/2}]+[Tds×{(Vfds+Vids)/2}]  (Equation5)Dw+Dm=dP  (Equation 6)Tap=(Vfap−Viap)/ap  (Equation 7)Tdp=(Vfdp−Vidp)/dp  (Equation 8)Tas=(Vfas+Vias)/as  (Equation 9)Tds=(Vfds+Vids)/ds  (Equation 10)

Where,

Dw=Distance from sorter window to rendezvous point

Vw=Velocity of sorter window, which may be constant in some embodiments

Trp=Time to rendezvous point for sorter window and the article

Dm=Distance from article to rendezvous point

Tap=Time for article to accelerate in picking zone

Tdp=Time for article to decelerate in picking zone

Tc=Time for article to run at constant speed in either picking zone orsynchronization device

Tas=Time for article to accelerate in synchronization device

Tds=Time for article to decelerate in synchronization device

Trp=Time for the article to reach the rendezvous point(Trp=Tap+Tdp+Tc+Tas+Tds)

Vfap=Final velocity after acceleration move in the picking zone

Viap=Initial velocity before acceleration move in the picking zone

Vfdp=Final velocity after deceleration move in the picking zone

Vidp=Initial velocity before deceleration move in the picking zone

Vc=Constant velocity for article in either picking zone orsynchronization device

Vfas=Final velocity after acceleration move in the synchronizationdevice

Vias=Initial velocity before acceleration move in the synchronizationdevice

Vfds=Final velocity after deceleration move in the synchronizationdevice

Vids=Initial velocity before deceleration move in the synchronizationdevice

dP=Distance between the article and the sorter window

ap=Acceleration rate in the picking zone

as=Acceleration rate in the synchronization device

dp=Deceleration rate in the picking zone

ds=Deceleration rate in the synchronization device

The above equations may be solved, for example, using a controller orprocessor, to determine if an article can be assigned to a sorterwindow, which means the article can be synchronized to the sorter windowbased on the initial conditions. The controller or processor may beimplemented with any combination of general-purpose microprocessors,microcontrollers, digital signal processors (DSPs), field programmablegate array (FPGAs), programmable logic devices (PLDs), controllers,state machines, gated logic, discrete hardware components, dedicatedhardware finite state machines, or any other suitable entities that canperform calculations or other manipulations of information. If theinitial conditions do not allow synchronization of the article with thecurrently available sorter window, the article may wait for the nextavailable window or may be rejected in the event the article is tooclose to the end of the article feeder system. If it is determined thatthe article can be synchronized with a sorter window, the velocityprofile is determined. The above set of expanded equations (Equations4-10) may be solved to determine the velocity profile required for thearticle to be synchronized based on the initial conditions. The traveltimes for the sorter window and the article to reach the rendezvouspoint are the same starting from the initial conditions. The traveldistances for the sorter window and the article will vary based on theinitial conditions.

The system may adjust the velocity profile of each article with eachscan of the control logic as conditions change. For example, theexpanded set of equations (Equations 4-10) may be used to adjust thevelocity profile of the article as the article travels downstream basedon sensor feedback. Sensors may include edge detector sensors, such asphotoelectric or photo-eye sensors or a proximity sensor. Because themotivation for the articles is not positive, the articles may slip asthey move toward the exit of the article feeder system. Sensors may bepositioned along the article path so that the leading edge position ofeach article may be determined and/or confirmed. This position feedbackensures a high degree of synchronization accuracy between the articleand the sorter window. Accordingly, the synchronization may be based onarticle position feedback from sensors located along the article flowpath, which may sense the position of the article as it is conveyeddownstream by the picking zones and the synchronization device. Thus,the velocity profile for an article may be adjusted based on itsposition through the picking zones and the synchronizer (if present).

FIG. 15 is a flow chart depicting one embodiment of a method 1500 ofdetermining a velocity or movement profile. At block 1502, a nextcontroller scan is started. At each scan of the control logic, themethod continues to block 1504 and solves equation 4 for Trp to obtainthe equation Trp=Dw/Vw. As noted above, Trp is the time for the articleto reach the rendezvous point, Dw is the distance from the next sorterwindow to the rendezvous point, and Vw is the velocity of the nextsorter window, which is constant. Dw and Vw are known and are used tocalculate Trp.

At block 1506, equation 5 may be solved for Vfap, Vfdp, Vc, Vfas, Vfds,Tap, Tdp, Tc, Tas, and Tds. Equation 5 defines the velocity or motionprofile of the article at any given point. Equations 6-10 may be used tosolve equation 5 for these variables. Dm is the distance from thearticle to rendezvous point, and is known, for example, based on one ormore sensors located proximate to the picking zones along the articleflow path. The acceleration rate in a given picking zone (ap), thedistance between the article and the next sorter window (dp), theacceleration rate in the synchronization device (as), and thedeceleration rate in the synchronization device (ds) are all known andare all constants. Trp is known from block 1504. Furthermore, it isknown that Trp=Tap+Tdp+Tc+Tas+Tds. Tap is the time for the article toaccelerate in a picking zone, Tdp is the time for the article todecelerate in the picking zone, Tc is the time for the article to run ata constant speed in either the picking zone or a synchronization device,Tas is the time for the article to accelerate in the synchronizationdevice, and Tds is the time for article to decelerate in thesynchronization device. The initial velocity conditions Viap, Vidp,Vias, and Vids are also known. Viap is the initial velocity before beingaccelerated in the picking zone, Vidp is the initial velocity beforebeing decelerated in the picking zone, Vids is the initial velocitybefore being decelerated in the synchronization device, and Vias is theinitial velocity before being accelerated in the synchronization device.

At block 1508, equation 5 may be used to determine and/or adjust thevelocity or motion profile of the article at any given point using theseknown constants and variables. In particular, equation 5 may be used todetermine and/or adjust the velocity or motion profile of the article bysolving for the final velocity for the article after being acceleratedin the picking zone (Vfap), the final velocity for the article afterbeing decelerated in the picking zone (Vfdp), the constant velocity forthe article in either the picking zone or the synchronization device(Vc), the final velocity for the article after being accelerated in thesynchronization device (Vfas), the final velocity for the article afterbeing decelerated in the synchronization device (Vfds), the time for thearticle to accelerate in the picking zone (Tap), the time for article todecelerate in the picking zone (Tdp), the time for the article to run atconstant speed in either the picking zone or the synchronization device(Tc), the time for the article to accelerate in the synchronizationdevice (Tas), and the time for article to decelerate in synchronizationdevice (Tds).

From block 1508, the process 1500 returns to block 1502 when a nextcontroller scan begins. For example, the method may adjust the velocityor movement profile of each article with each scan of the control logicas conditions change so that the velocity profile for an article may beadjusted based on its position through the picking zones and thesynchronizer (if present).

Returning to FIG. 9A, an overhead view of an article feeder system 102is illustrated. The article feeder system 102 allows for a floating orvarying pick point and also for the continuous synchronization of theeach article with a desired sorting window based on feedback fromsensors 912, 914, and 920. The sensors may include proximity sensors oredge detector sensors, such as photoelectric, photo-eye, infrared,optical sensors, and the like. The article feeder system 102 includes abelt that carries a stack of articles 202 moving in the direction of thearrow 126. The stack of articles 202 is at a distance 908 from anarticle guide. The article feeder system 102 includes a plurality ofpicking devices 110, including picking devices S1-S5 that each includesa perforated belt 606 and a vacuum system 916, including vacuum systemsV1-V5. Each of vacuum the systems V1-V5 may include a vacuum unit, avacuum manifold 608, and a vacuum valve 616, as illustrated in FIG. 6B.Each of the picking devices may further include a vacuum unit and avacuum valve, as described above. The sensors 912, 914, and 920 may beused to provide feedback. For example, sensor 912 may be used to detecta leading edge of the stack of articles 202. The remaining sensors 914and 920 may be used to continuously indicate a position of the stack ofarticles 202 and/or the position of a singulated article picked by oneof the picking devices S1-S5.

As noted above, in some embodiments, the article feeder system 102 maynot include a dedicated shingulating device or a dedicatedsynchronization device. In some embodiments, the article feeder system102 may not include a dedicated shingulating device, but may include adedicated synchronization device. In some embodiments, the articlefeeder system 102 may not include a dedicated synchronization device,but may include a dedicated shingulating device. In these embodiments,the picking devices S1-S5 may perform parallel shingulation,singulation, and/or synchronization while allowing for anti-doublingusing one or more anti-doubling devices 112 located across from one ormore picking devices. In some embodiments, the article feeder system 102may include both a dedicated shingulating device and a dedicatedsynchronization device to assist in the shingulation andsynchronization, similar to the article feeder system 102 illustrated inFIG. 1.

In some embodiments, virtual windows may be used to synchronize eacharticle with a sorter window using the article feeder system 102. FIG.9B illustrates an example of an article feeder system 102 operatingusing virtual windows. The article feeder system 102 includes pickingzones P1-P5, sensors 904, and virtual windows 902 and 906. Each of thesensors 904 may correspond to any of the sensors 914, 920, and 912 ofFIG. 9A. Each of the picking zones P1-P5 may include vacuum systems 916,including V1-V5. Each of vacuum systems V1-V5 may include a vacuum unit,a vacuum manifold 608, and a vacuum valve 616, as illustrated in FIG.6B. Each of the picking zones P1-P5 also includes a picking device, suchas that described above with respect to FIGS. 6B and/or 9A. One or moreof the picking zones P1-P5 may include an anti-doubling device oppositethe picking device. As described above with respect to FIGS. 7A-7B, somecombination of the anti-doubling devices may have a low level ofconstant vacuum to promote shingulation of the articles. For example,picking devices S1 and S2 of FIG. 9A may have a low level of constantvacuum power to shingulate the articles. As the edge detector sensor 610and the presence sensor 612 detect more than one article (e.g., if anundesired article is stuck to a desired article after being picked andsingulated), an anti-doubling device associated with one of the pickingdevices S3-S5 may be turned on to full vacuum in order to separate anyarticles from the desired article that is to be singulated by thepicking zone.

Each of the picking devices further includes a perforated belt 606 (notshown in FIG. 9B). Each of the perforated belts 606 may be driven usinga dedicated motor and/or gearbox (not shown). For example, a servo-motormay be used, such as a KollMorgen C042B high-torque, low-speed,bering-less, direct-drive cartridge motor or a KollMorgen C041B motor.FIG. 9C illustrates an example of a pulley system for driving aperforated belt 606 of a picking device 110. A drive pulley 922, atensioner pulley 924, and two front idler pulleys 926 under the controlof a controller or processor (not shown) may be used to drive the belt606 of each of the picking devices in order to coordinate the movementof a group of articles. The controller or processor may be implementedwith any combination of general-purpose microprocessors,microcontrollers, digital signal processors (DSPs), field programmablegate array (FPGAs), programmable logic devices (PLDs), controllers,state machines, gated logic, discrete hardware components, dedicatedhardware finite state machines, or any other suitable entities that canperform calculations or other manipulations of information.

In some embodiments, a flat belt may be used as the perforated belt 606that does not include any tracking or teeth along the middle of thebelt. In some embodiments, a perforated timing belt may be used as theperforated belt 606. A perforated timing belt is easy to tension, willnot slip on the drive pulley 922, has a built-in tracking feature, anddoes not require a take-up pulley. FIG. 9D illustrates an example of aperforated timing belt 928. The built-in tracking feature 930 along thecenter of the timing belt may remove the need for crowned pulleys whichmay decrease cost of the system. The built-in tracking feature 930 mayinclude timing teeth to allow the use of a plain metal drive pulleyrather than a lagged pulley, which may also decrease cost. In someembodiments, a plain rib may be used on the timing belt 928 instead ofthe timing teeth, which may provide a better tracking feature at theexpense of pulley grip. The majority of the tension in the timing belt928 is transmitted through the timed center built-in tracking feature930. Accordingly, larger holes may be included in the remainder of theperforated timing belt 928 because this portion of the timing belt 928is not primarily used to move the belt.

Returning to FIG. 9B, each of the virtual windows 902 and 906 includes aposition on the article feeder system 102 at which a leading edge of anarticle (e.g., article 910) must be located in order for the article tobe deposited into a corresponding sorter window. The above equations1-10 may be used to program a controller or processor to cause thearticle feeder system 102 to align the leading edge of each article witha current un-booked virtual window. The controller or processor may beimplemented with any combination of general-purpose microprocessors,microcontrollers, digital signal processors (DSPs), field programmablegate array (FPGAs), programmable logic devices (PLDs), controllers,state machines, gated logic, discrete hardware components, dedicatedhardware finite state machines, or any other suitable entities that canperform calculations or other manipulations of information. The articlefeeder system 102 may start the picking process from standstill at anygiven picking zone while maintaining synchronization with a virtualwindow 902 and/or 906. The system 102 may provide continuoussynchronization with the virtual windows 902 and/or 906 to provideefficient and continuous feeding of articles. For example, each pickingzone P1-P5 may monitor a next un-booked virtual window position inrelation to its own position along the article picking route. Thepicking zones P1-P5 may be configured to coordinate synchronizedmovement with one another in order to translate the articles so that theleading edge of each article is on target with one of the virtualwindows 902 and/or 906. The velocity profiles described above may beused to coordinate the synchronized movement of the picking zonecomponents. The sensors 904 along the article travel path may providefeedback regarding the exact position of the leading edge of eacharticle at a given point in time. The leading edge feedback position maybe compared to the position where the article should be in relation tothe corresponding virtual window 902 or 906. This data may be used tomodify the current article velocity profile to reposition andresynchronize the article with the virtual window.

FIG. 10 illustrates an example of an article feeder system 102 that maybe used to properly synchronize each of the articles with a sortingwindow using virtual windows. The article feeder system 102 includes apick zone operation 1004 for controlling the picking zones 1008,including picking zones 1-5. The picking zone operation 1004 includesvacuum control, correction control, doubles detection, and errormonitoring. The article feeder system 102 further includes virtualwindow detection and virtual axis manager 1006. The pick zone operation1004 and the virtual window detection and virtual axis manager 1006 maybe implemented using a controller or processor (not shown). Thecontroller or processor may be implemented with any combination ofgeneral-purpose microprocessors, microcontrollers, digital signalprocessors (DSPs), field programmable gate array (FPGAs), programmablelogic devices (PLDs), controllers, state machines, gated logic, discretehardware components, dedicated hardware finite state machines, or anyother suitable entities that can perform calculations or othermanipulations of information. For example, one or more software orcomputer programs may be developed to cause the controller or processorto implement the pick zone operation 1004 and the virtual windowdetection and virtual axis manager 1006.

FIG. 11A illustrates an example of controlling a virtual axis using thevirtual window detection and virtual axis manager 1006. The mastervirtual axis 1102 may be the reference point upon which the virtualwindows 1104-1108 are based upon. For example, virtual window (VW)pulses 1-3 for each of the virtual windows 1104-1108 may be generated ata fixed interval at the line speed rate (e.g., 3.15 m/s) using themaster virtual axis 1102 as a reference point. Based on the mastervirtual axis 1102, all components of the article feeder systemsdescribed above may be controlled in order to synchronize each articlewith a sorter window by aligning the leading edge of each article with acorresponding virtual window.

FIG. 11B illustrates an example of synchronizing an initial article 1110with a sorter window using the pick zone operation 1004. As the processof picking one or more articles from a stack of articles 202 or 302begins, the article feeding system 102 is started and the initialarticle 1110 is ready to be picked. As the system is started, thevirtual axis is error free and is moving at the line speed rate (e.g.,3.15 m/s), and the virtual windows are detected. The downstream pickingzones, the vacuum systems 916 (e.g., vacuum unit, a vacuum manifold, anda vacuum valve), the belts, and the synchronization device(s) (ifpresent) are clear and ready to begin operation.

After the picking process has begun, the picking and singulation of eacharticle takes place on a zone available basis, such that the downstreammost available picking zone is selected to pick an article. The nextavailable virtual window is assigned to the furthest upstream article tobe picked so that the leading edge of that article is aligned with thevirtual window. The position of each of the articles is known based onthe feedback from the sensors. One or more of the picking zones worktogether in the synchronization process. Each of the picking zonesoperate independently of each other, but may be simultaneously handeddown motion commands by the pick zone operation 1004 to achievesynchronization among the picking zones. The pick zone operation 1004instruct one or more of the picking zones to turn on and control thespeed at which each of the picking zones operate in order to align theleading edge of the article 1110 with the virtual window 1104. Forexample, the pick zone operation 1004 may command a picking zone tooperate at a particular gear ratio between the master axis and each ofthe slave axes from a synchronization point onward. The gear ratio mayprovide the acceleration and deceleration of the perforated belt of eachpicking device to speed up and slow down the article 1110 as it movesacross the picking zones. FIG. 11C illustrates an example ofcoordinating the operation of the picking zones with master and slaveaxes to control the picking of the article 1110. A mastersynchronization point 1112, master start distance 1114, slave startdistance 1116, and acceleration and velocity limitations define how theslave axis for each particular picking zone moves at the commandedmaster speed according to a final gear ratio determined for that pickingzone. The picking zones operate by detecting a leading edge of nextpicked article based on the sensors located at each picking zone. Theavailable picking zones that are available to take part in thesynchronization are determined along with parameters for start distancesand synchronization positions. Once the available picking zones and theparameters are determined, the pick zone operation 1004 commands theavailable picking zones to translate the article 1110 being picked insynchronization with the assigned virtual window. As a virtual window1104 passes through a picking zone and/or an article 1110 is clearedthrough the picking zone, the zone may be un-geared and stopped, thevacuum systems 916 may be turned off, and the picking zones are preparedfor the next virtual window if that picking zone is chosen in thepicking and synchronization of an article with that virtual window.

The vacuum systems 916 of each picking zone may be variably controlledby the pick zone operation 1004 according the position of the articlessensed by the various sensors at each picking zone. FIG. 12A illustratesan article feeder system 102 including picking zones 1204 and sensors1206. The sensors 1206 may include proximity sensors or edge detectorsensors, such as photoelectric, photo-eye, infrared, optical sensors,and the like. Each of the sensors 1206 may correspond to any of thesensors 914, 920, and 912 of FIG. 9A and/or sensors 904 of FIG. 9B. Asillustrated in FIG. 12A, four sensors are provided for each pickingzone. A person of skill in the art will understand that more or lesssensors may be included as needed. The vacuum systems 916 operate tohold the articles against the perforated transfer belts duringsynchronization as the article being picked is transferred downstreamalong the article feeder system. The third downstream sensor of eachpicking zone operates to cause actuation of the vacuum of each zone. Asa result, a picking zone cannot be turned on to take control of anarticle until the third sensor of that picking zone has been blocked byan article. For example, a picking zone may be actuated when a leadingedge of an article blocks the third downstream sensor of that pickingzone. The picking zone cannot give up control of article until thefourth downstream sensor of the next picking zone has been blocked. Thevacuum valve outputs and travel path sensor inputs may be controlled andmonitored via high speed input/outputs.

FIG. 12B illustrates an exemplary process of variably controlling thevacuum systems 916 of the picking zones based on the sensor feedback inorder to transfer the article 1208 downstream along the article feedersystem 102. As noted above, each of the vacuum systems 916 may include avacuum unit, a vacuum manifold, and a vacuum valve. At time 1 (T1), thearticle 1208 crosses over and blocks sensor 3, which is the thirddownstream sensor of the picking zone 1. Accordingly, sensor 3 operatesto cause actuation of the vacuum of picking zone 1. Because picking zone1 is the first picking zone, the system waits for next approachingvirtual window and gives picking zone 1 a response notice time period todevelop the vacuum. During the response notice time period, the pickingzone 1 vacuum is enabled and is developed to full vacuum strength. Oncefull vacuum strength is developed, picking zone 1 has control of thearticle 1208. Each picking zone may include a picking device and mayalso include an anti-doubling device. As described above with respect toFIG. 6B, a picking device may include a perforated belt, a perforatedbelt drive pulley, and the vacuum system. As the article 1208 movestoward the perforated belt, the vacuum valve is opened to develop thefull vacuum strength and the vacuum manifold is exposed to the vacuumforce. The vacuum force is used to pull the article 1208 from a stack ofarticles (if not already singulated) through the one or more openings ofthe perforated belt to effectively connect the article 1208 to theperforated belt. The article 1208 is held to the surface of theperforated belt by the vacuum force exerted on the article through theone or more holes in the perforated belt and is accelerated forward byan acceleration amount. In some embodiments, the pick zone operation1004 may instruct the picking zone 1 to decelerate in order tosynchronize the article 1208 with the virtual window.

At time 2 (T2), the article 1208 crosses over sensor 7, which is thethird downstream sensor of picking zone 2. At this point, the vacuumsystem of picking zone 2 is actuated. However, picking zone 1 still hascontrol of the article 1208. Thus, the vacuum of picking zone 2 isactuated prior to picking zone 2 taking control of the article 1208 frompicking zone 1. The time period from when picking zone 1 has control ofthe article 1208 to the point when picking zone 1 relinquishes controlto picking zone 2 gives time for the vacuum of picking zone 2 to developsufficient vacuum strength to drive the article 1208 downstream.

As noted above, picking zone 1 cannot give up control of article 1208until the fourth downstream sensor of the next picking zone (pickingzone 2) has been blocked. At time 3 (T3), the article 1208 crosses oversensor 8, which is the fourth downstream sensor of picking zone 2. Oncesensor 8 is blocked, picking zone 1 may relinquish control of thearticle 1208 to picking zone 2. At this point, the vacuum of pickingzone 1 is turned off. In some embodiments, the remaining components ofpicking zone 1 may be turned off, including the pulleys and gearsdriving the perforated belt and the anti-doubling device (if present inpicking zone 1). At T3, the vacuum of picking zone 2 is at a sufficientstrength so that picking zone 2 has full control and is responsible fordriving the article 1208 downstream along the article feeder system 102.

At time 4 (T4), the article 1208 crosses over and blocks sensor 11.Because sensor 11 is the third downstream sensor of picking zone 3, thevacuum of picking zone 3 is actuated to give the vacuum sufficient timeto develop enough vacuum force to control the article 1208. Picking zone2 still has full control of the article 1208, and does not pass controlto picking zone 3 until the fourth downstream sensor of picking zone 3is blocked.

At time 5 (T5), the article 1208 crosses over sensor 12, causing pickingzone 2 to relinquish control of the article 1208 to picking zone 3. Atthis point, the vacuum of picking zone 2 is turned off. The remainingcomponents of picking zone 2 may also be turned off, including thepulleys and gears driving the perforated belt and the anti-doublingdevice (if present in picking zone 2). At T5, the vacuum of picking zone3 is at a sufficient strength to allow picking zone 3 to have fullcontrol of the article 1208. At this point, picking zone 3 isresponsible for driving the article 1208 downstream along the articlefeeder system 102 to the next picking zone.

The process of variably controlling the vacuum systems of the pickingzones continues until the article 1208 reaches the most downstreampicking zone of the article feeder system 102. For example, if fivepicking zones are present, the process continues through picking zone 5until the article 1208 transition to either the sorting window or to asynchronization device pinch wheel (if present in the article feedersystem).

The pick zone operation 1004 further provides correction control inorder to ensure that an article is synchronized with a virtual window.The movement using the motors and gear ratio of the picking zoneperforated belts 606 can be precisely controlled using the virtualwindow detection and virtual axis manager 1006 so that the belts 606stay synchronized with the virtual window. However, the position of thearticles on the perforated belts 606 cannot be guaranteed due to variouseffects upon the articles as they move along the belts 606, such asslippage of the articles, gusts of air, slumping, and the like. FIG. 13illustrates an example of an article feeder system 102 using the pickzone operation 1004 for correction control. The sensors 1206 may be usedto detect the position of the article 1304 as it is synchronized throughthe article feeder system 102. The sensors 1206 may include proximitysensors or edge detector sensors, such as photoelectric, photo-eye,infrared sensors, optical sensors, and the like. The position of thearticle 1304, as detected by one or more of the sensors 1206, may becompared to the corresponding virtual window position at the trigger ofeach sensor in order to determine the absolute error of article 1304position. This error value may be fed into a picking zone controller orprocessor (not shown), and the pick zone operation 1004 may operate toposition and re-track the article 1304 so that the article 1304 isre-synchronized with the corresponding virtual window. For example, thepick zone operation 1004 may instruct one or more picking zones toaccelerate or decelerate the article 1304 and may control the vacuumsaccordingly as described above in order to re-synchronize the article1304 and the virtual window. The picking zone controller or processormay be implemented with any combination of general-purposemicroprocessors, microcontrollers, digital signal processors (DSPs),field programmable gate array (FPGAs), programmable logic devices(PLDs), controllers, state machines, gated logic, discrete hardwarecomponents, dedicated hardware finite state machines, or any othersuitable entities that can perform calculations or other manipulationsof information.

The absolute error is updated by the pick zone operation 1004 on eachcycle of a triggered sensor and may be stored to a particular value.Each of the picking zones participating in the synchronized motion forsynchronizing the article 1304 with the virtual window may receive thesame value storing the absolute error. The participating picking zonesmay use the value to execute an offset to synchronize the article 1304back in line with the virtual window. In some embodiments, a maximumerror limit may be determined based on the position of the article 1304and the corresponding error relative to the virtual window. If theabsolute error as detected by the sensors 1206 indicates that thismaximum error limit has been exceeded, the pick zone operation 1004 maydetermine that the article 1304 needs to give up on the current virtualwindow and may assign the article 1304 to the next available window.

By providing for correction control, the article feeder system 102 mayprovide real time error compensation at high speed using the feedbackfrom the sensors 1206 so that positive and negative shifts of thearticle 1304 can be compensated for.

In some embodiments, the sensors 1206 may be used to aid inanti-doubling. For example, the sensors 1206 may detect if an articleappears to be getting longer or if an article appears to turn into twoarticles during travel due to an attached article to the desiredarticle. The anti-doubling devices may be used to separate the attachedarticle, which may be assigned to the next available virtual window.

In some embodiments, movement profiles may be generated in order toreduce acceleration damage to the articles as they are moved along thearticle feeder systems described above. In some embodiments, themovement profile may be the same as the velocity profile describedabove, and may be calculated using equations 1-10 and/or according toFIG. 15 described above. For example, article damage may occur as thearticle is accelerated and/or decelerated along the shingulating and/orpicking devices. For example, mail pieces with covers that have lessstructural integrity, such as mail with thin glossy staple bound covers,may damage more easily. As another example, open mail may damage moreeasily than mail that is in an envelope. As used herein, open mailrefers to an article (e.g., a periodical, magazine, and the like) thatis bound along one edge only and is open along the other three edges. Asdescribed above, the articles are accelerated from the stack of articlesto a velocity required for synchronization with a sorter window (e.g.,using virtual windows). As the processing rate and the length of thearticles increases, the design acceleration and deceleration must beincreased. The perforated belts of the picking devices translate thearticles by accelerating and decelerating the articles from one side ofthe article, and high acceleration or deceleration rates may cause highinertial forces. These inertial forces are proportional to theacceleration and deceleration rate. As an article is accelerated ordecelerated, the inertial forces generated in the main body of thearticle resist the change in velocity. This resistance imparts shearingforces and torque on the side being translated by the picking device,which may cause damage to the article.

The movement profiles may be designed to cause the article feeder systemto operate with the lowest possible constant acceleration anddeceleration rates while allowing the system to meet the overall desireddesign rate with the longest article. In order to reduce the effectiveacceleration and/or deceleration experienced by an article when pickedand singulated, the movement profile may stop the perforated belt foreach pick, open the vacuum valve and wait for the vacuum to develop, andaccelerate the article being picked at the lowest possible accelerationrate while assuming the longest possible article is being picked. Thearticle is accelerated at the lowest possible acceleration rate bygradually ramping up the speed of the perforated belt in a controlledmanner. The vacuum is not energized as the perforated belt isaccelerated because if the vacuum does not develop quickly enough, theeffective acceleration may be higher than the rate executed by the motorof the belt. Instead, the acceleration is not ramped up until the vacuumhas developed. The system may sense the vacuum level in the manifoldafter the valve is energized. The feedback regarding the vacuum levelmay be generated using a valve with spool sensors and/or a vacuum gauge.Once the vacuum has been established, the motor may execute the movementprofile. The lowest acceleration is determined by the longest designarticle and the design processing rate, which determines the rate atwhich articles are singulated from the stack of articles. If a dedicatedsynchronization device is present, the articles can be more aggressivelyaccelerated in the synchronization device because the articles arestabilized by being pushed together and driven on both sides by thepinch wheels. Accordingly, in some embodiments, the movement profilesmay only be used with the shingulating and picking devices.

Use of the movement profiles may result in less article damage. Themovement profiles may also allow for more precise article motion alongthe article feeder system because the vacuum system may be used moreefficiently. The more precise motion of the articles along the systemmay help in synchronizing the articles with the sorting windows.

FIG. 14 is a flowchart of an embodiment of a process 1400 for managingarticles in an article feeder 102. Process 1400 may commence when thestack of articles 202 is placed on the conveyor 104. The process 1400proceeds to block 1402 a stack of articles 202 is received at ashingulating device 108 and a positively lapped stack of articles 302 isproduced. The stack of articles 202 is shingulated to produce thepositively lapped stack of articles 302. Any of the embodiments of theshingulating device 108 described above may be used to shingulate thestack of articles. As used herein, the term shingulate or shingulationmay refer to the process of extruding the stack 202 to produce apositively lapped stack of articles 302. At block 1404, one or morearticles are picked from the positively lapped stack of articles 302using one or more picking devices 119 and one or more singulatedarticles are produced. Any of the singulating devices 110 disclosedherein may be used to pick and singulate an article from the stack 302.Singulation, as described herein, uses a vacuum force to attract andhold an article to the perforated belt, which transports a singlearticle downstream along the article feeder. At block 1406, the one ormore singulated articles are delivered to one or more sorter windowsusing one or more synchronization devices 114. The synchronizationdevice 114 described above may be used to deliver the singulatedarticles to the sorter windows.

In some embodiments, producing the positively lapped stack of articles302 comprises moving the stack of articles 202 toward a shearing device408 using a bottom transport belt 404 and a perforated belt 406 of theshingulating device 108 and applying a shearing force on the stack ofarticles using the shearing device 408. The bottom transport belt 404has a transport surface extending in a first direction and theperforated belt 406 has a surface extending in a second directiondifferent than the first direction. The first direction may be asubstantially horizontal direction and the second direction may be asubstantially vertical direction relative to the bottom transport belt.For example, the perforated belt 406 may be at a right angle relative tothe generally horizontal direction of the bottom transport belt 404. Theperforated belt 406 is adjacent to the bottom transport belt 404 and maybe configured to be moved in the downstream direction toward theshearing device 408 using one or more belt drives 410.

In some embodiments, the process 1400 further comprises applying suctionthrough one or more openings in the perforated belt 406 using a vacuumsystem. For example, one or more articles may be held to the surface ofthe perforated belt 406 by a vacuum force exerted on the article throughthe one or more openings in the perforated belt 406. The stack ofarticles 202, being held against the perforated belt and resting on thebottom transport belt, may be moved in the downstream direction towardthe shearing device 408.

In some embodiments, picking the one or more articles from thepositively lapped stack of articles 302 comprises opening a vacuum valve616 of a first picking device 110 to expose a vacuum manifold 608 of thefirst picking device 110 to suction from a vacuum unit, applying thesuction from the vacuum manifold 608 through one or more openings in aperforated belt 606 of the first picking device 110 to one of the one ormore articles, and attaching the article to the perforated 606 beltusing the suction through the one or more openings. In some embodiments,producing the one or more singulated articles comprises separating anarticle from the positively lapped stack of articles 302 by driving theperforated belt 606 with the attached article forward using a motor. Insome embodiments, the singulated article is picked and produced by adownstream most picking device in a row of picking devices that issubstantially completely covered by the positively lapped stack ofarticles.

In some embodiments, the process 1400 further comprises preventing morethan one article at a time from being picked from the positively lappedstack of articles 302 using an anti-doubling device 112 located in arespective picking zone, each respective picking zone including arespective picking device 110 and an anti-doubling device 112. Ananti-doubling device 112, such as that described above, may be used toprevent more than one article from being picked at a time using, forexample, the process described above with respect to FIG. 7B. Forexample, the process 1400 may further comprise detecting a first articleusing a presence sensor 612 of the anti-doubling device, detecting anedge of a second article using an edge detector sensor 610 of theanti-doubling device, the edge detector sensor 610 being positionedupstream from the presence sensor 612, and applying suction to thesecond article using a vacuum unit of the anti-doubling device 112 whenthe presence sensor 612 detects the first article during a time periodin which the edge detector sensor 610 detects the edge of the secondarticle.

In some embodiments, the process 1400 further comprises controllingmovement of each article of the stack of articles to synchronize a firsttime when each of the one or more singulated articles reaches an exitpoint with a second time when a sorter window reaches the exit point.The exit point corresponds to the rendezvous point 116 described above.For example, the virtual windows described above with respect to FIGS.9B, 10, and 11A-C may be used to synchronize an article with a sortingwindow. In some embodiments, the synchronization of the first time withthe second time is based on one or more of a location of a first articlebeing picked by a first picking device, a velocity of the first article,a location of the sorter window, a velocity of the sorter window, anacceleration rate of each of a plurality perforated belts included ineach of the plurality of picking devices, an acceleration rate of theone or more synchronization devices, a maximum velocity allowed for eachof the plurality perforated belts included in each of the plurality ofpicking devices, a maximum velocity allowed for a perforated beltincluded in the shingulating device, a maximum velocity allowed for theone or more synchronization devices, a length of each of the pluralityof perforated belts included in each of the plurality of pickingdevices, a length of the perforated belt included in the shingulatingdevice, a number of perforated belts, a length of the one or moresynchronization devices, and a number of the one or more synchronizationdevices.

In some embodiments, the shingulation, picking and shingulation, andsynchronization of process 1400 may be accomplished using only thepicking zones, including the picking devices 110, anti-doubling devices112, edge detector sensors 610, and/or presence sensors 612. Forexample, as described above, an article feeder system may allow the pickpoint at which the stack of articles transitions from shingulated tosingulated to float or vary using variably controlled picking zones.

An article feeder system 102 may also comprise means for receiving astack of articles 202 to produce a positively lapped stack of articles302; means for picking an article from the positively lapped stack ofarticles 302 to produce one or more singulated articles; and means fordelivering the singulated article to a sorter window. In someembodiments, the means for receiving a stack of articles may include anyof the embodiments of the shingulating device 108 described above. Insome embodiments, the means for picking an article from the positivelylapped stack of articles may include any of the singulating devices 110disclosed herein. In some embodiments, the means for delivering thesingulated article may include the synchronization device 114 describedabove. In some embodiments, the group of singulating devices, such asdevices 110 described above, may be used to shingulate, pick, singulate,and synchronize the articles. For example, the article feeder system 102may allow the pick point at which the stack of articles 302 transitionsfrom being shingulated to being singulated to float or vary usingvariably controlled picking devices.

The technology is operational with numerous other general purpose orspecial purpose computing system environments or configurations.Examples of well-known computing systems, environments, and/orconfigurations that may be suitable for use with the invention include,but are not limited to, personal computers, server computers, hand-heldor laptop devices, multiprocessor systems, microprocessor-based systems,programmable consumer electronics, network PCs, minicomputers, mainframecomputers, distributed computing environments that include any of theabove systems or devices, and the like.

As used herein, instructions refer to computer-implemented steps forprocessing information in the system. Instructions can be implemented insoftware, firmware or hardware and include any type of programmed stepundertaken by components of the system.

A microprocessor may be any conventional general purpose single- ormulti-chip microprocessor such as a Pentium® processor, a Pentium® Proprocessor, a 8051 processor, a MIPS® processor, a Power PC® processor,or an Alpha® processor. In addition, the microprocessor may be anyconventional special purpose microprocessor such as a digital signalprocessor or a graphics processor. The microprocessor typically hasconventional address lines, conventional data lines, and one or moreconventional control lines.

The system may be used in connection with various operating systems suchas Linux®, UNIX® or Microsoft Windows®.

The system control may be written in any conventional programminglanguage such as C, C++, BASIC, Pascal, or Java, and ran under aconventional operating system. C, C++, BASIC, Pascal, Java, and FORTRANare industry standard programming languages for which many commercialcompilers can be used to create executable code. The system control mayalso be written using interpreted languages such as Perl, Python orRuby.

Those of skill will further recognize that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the embodiments disclosed herein may be implemented aselectronic hardware, software stored on a computer readable medium andexecutable by a processor, or combinations of both. To clearlyillustrate this interchangeability of hardware and software, variousillustrative components, blocks, modules, circuits, and steps have beendescribed above generally in terms of their functionality. Whether suchfunctionality is implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem. Skilled artisans may implement the described functionality invarying ways for each particular application, but such embodimentdecisions should not be interpreted as causing a departure from thescope of the present invention.

The various illustrative logical blocks, modules, and circuits describedin connection with the embodiments disclosed herein may be implementedor performed with a general purpose processor, a digital signalprocessor (DSP), an application specific integrated circuit (ASIC), afield programmable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. The steps of a method or algorithm disclosedherein may be implemented in a processor-executable software modulewhich may reside on a computer-readable medium. Computer-readable mediaincludes both computer storage media and communication media includingany medium that can be enabled to transfer a computer program from oneplace to another. A storage media may be any available media that may beaccessed by a computer. By way of example, and not limitation, suchcomputer-readable media may include RAM, ROM, EEPROM, CD-ROM or otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium that may be used to store desired programcode in the form of instructions or data structures and that may beaccessed by a computer. Also, any connection can be properly termed acomputer-readable medium. Disk and disc, as used herein, includescompact disc (CD), laser disc, optical disc, digital versatile disc(DVD), floppy disk, and Blu-ray disc where disks usually reproduce datamagnetically, while discs reproduce data optically with lasers.Combinations of the above should also be included within the scope ofcomputer-readable media. Additionally, the operations of a method oralgorithm may reside as one or any combination or set of codes andinstructions on a machine readable medium and computer-readable medium,which may be incorporated into a computer program product.

The foregoing description details certain embodiments of the systems,devices, and methods disclosed herein. It will be appreciated, however,that no matter how detailed the foregoing appears in text, the systems,devices, and methods can be practiced in many ways. As is also statedabove, it should be noted that the use of particular terminology whendescribing certain features or aspects of the invention should not betaken to imply that the terminology is being re-defined herein to berestricted to including any specific characteristics of the features oraspects of the technology with which that terminology is associated.

It will be appreciated by those skilled in the art that variousmodifications and changes may be made without departing from the scopeof the described technology. Such modifications and changes are intendedto fall within the scope of the embodiments. It will also be appreciatedby those of skill in the art that parts included in one embodiment areinterchangeable with other embodiments; one or more parts from adepicted embodiment can be included with other depicted embodiments inany combination. For example, any of the various components describedherein and/or depicted in the Figures may be combined, interchanged orexcluded from other embodiments.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations may be expressly set forth herein for sakeof clarity.

It will be understood by those within the art that, in general, termsused herein are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced claim recitation is intended, such anintent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to embodiments containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should typically be interpreted to mean “atleast one” or “one or more”); the same holds true for the use ofdefinite articles used to introduce claim recitations. In addition, evenif a specific number of an introduced claim recitation is explicitlyrecited, those skilled in the art will recognize that such recitationshould typically be interpreted to mean at least the recited number(e.g., the bare recitation of “two recitations,” without othermodifiers, typically means at least two recitations, or two or morerecitations). Furthermore, in those instances where a conventionanalogous to “at least one of A, B, and C, etc.” is used, in generalsuch a construction is intended in the sense one having skill in the artwould understand the convention (e.g., “a system having at least one ofA, B, and C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). In those instances where aconvention analogous to “at least one of A, B, or C, etc.” is used, ingeneral such a construction is intended in the sense one having skill inthe art would understand the convention (e.g., “a system having at leastone of A, B, or C” would include but not be limited to systems that haveA alone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). It will be furtherunderstood by those within the art that virtually any disjunctive wordand/or phrase presenting two or more alternative terms, whether in thedescription, claims, or drawings, should be understood to contemplatethe possibilities of including one of the terms, either of the terms, orboth terms. For example, the phrase “A or B” will be understood toinclude the possibilities of “A” or “B” or “A and B.”

All references cited herein are incorporated herein by reference intheir entirety. To the extent publications and patents or patentapplications incorporated by reference contradict the disclosurecontained in the specification, the specification is intended tosupersede and/or take precedence over any such contradictory material.

The term “comprising” as used herein is synonymous with “including,”“containing,” or “characterized by,” and is inclusive or open-ended anddoes not exclude additional, unrecited elements or method steps.

All numbers expressing quantities of ingredients, reaction conditions,and so forth used in the specification and claims are to be understoodas being modified in all instances by the term “about.” Accordingly,unless indicated to the contrary, the numerical parameters set forth inthe specification and attached claims are approximations that may varydepending upon the desired properties sought to be obtained by thepresent invention. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical parameter should be construed in light of the number ofsignificant digits and ordinary rounding approaches.

The above description discloses several methods and materials of thepresent invention. This invention is susceptible to modifications in themethods and materials, as well as alterations in the fabrication methodsand equipment. Such modifications will become apparent to those skilledin the art from a consideration of this disclosure or practice of theinvention disclosed herein. Consequently, it is not intended that thisinvention be limited to the specific embodiments disclosed herein, butthat it cover all modifications and alternatives coming within the truescope and spirit of the invention as embodied in the attached claims.

What is claimed is:
 1. An article processing system comprising: aplurality of picking devices, each picking device configured to receiveand transport a first article from a plurality of articles, and eachpicking device comprising: a moveable belt having one or more openingsin its surface; a vacuum unit configured to apply a variable vacuumforce to the first article through the one or more openings in themoveable belt; and a sensor, wherein the sensor is configured to detecta leading edge of the first article; a controller in communication withthe sensor, the controller configured to: determine a current positionof the first article received on the movable belt of a first pickingdevice of the plurality of picking devices based on the sensor;determine a first virtual window for the first article; determine asynchronization position for the first article where the leading edge ofthe first article is synchronized with the first virtual window;determine a time and a speed of the first article required to rendezvousthe first article with a sorter window at a rendezvous point; and movethe movable belt of the first picking device to cause the first articleto contact a movable belt of a second picking device based on thesynchronization position.
 2. The system of claim 1, wherein theplurality of picking devices are independently controllable to controlthe speed of one or more of the plurality of articles.
 3. The system ofclaim 1, wherein to determine the first virtual window, the controlleris further configured to: determine a distance between the leading edgeof the first article and the rendezvous point; determine a speed and alocation of a sorter window; and determine a time required to acceleratethe first article to a required speed to rendezvous with the sorterwindow at the rendezvous point.
 4. The system of claim 1, wherein todetermine the synchronization position, the controller is furtherconfigured to: determine an initial speed of the first article;determine a rendezvous time required to move the first article via thefirst picking device to the rendezvous point; and compare the rendezvoustime required to move the first article to the rendezvous point and atime required to move the first virtual window to the rendezvous point.5. The system of claim 4, wherein the controller is further configuredto accelerate or decelerate the first article via the first pickingdevice and second picking device to match the speed and position of thefirst article with the speed and position of the virtual window at therendezvous point.
 6. The system of claim 4, wherein to rendezvous thefirst article with the sorter window at the rendezvous point, thecontroller is further configured to: determine a location of the sorterwindow; determine a current speed of the sorter window; determine asorter window time wherein the sorter window will reach the rendezvouspoint; compare the sorter window time to the rendezvous time; and movethe movable belt of the first picking device to cause the first articleto accelerate or decelerate to rendezvous with the sorter window at therendezvous point.
 7. The system of claim 6, wherein the current speed ofthe sorter window is constant.
 8. The system of claim 1, wherein thecontroller is further configured to: re-synchronize the position of theleading edge of the first article with the first virtual window and tomove the second picking device.
 9. The system of claim 1, furthercomprising a synchronization device disposed downstream of the pluralityof picking devices, configured to accelerate or decelerate the firstarticle with the virtual window at the rendezvous point.
 10. The systemof claim 9, wherein the synchronization device further comprises a setof pinch wheels.
 11. The system of claim 1, further comprising ananti-doubling device configured to prevent more than one article at atime from being picked.
 12. The system of claim 11, wherein theanti-doubling device is disposed opposite the first picking device. 13.The system of claim 11, further comprising at least a secondanti-doubling device, each anti-doubling associated with one of theplurality of picking devices.
 14. The system of claim 13, wherein eachof the anti-doubling devices further comprises at least one sensorconfigured to detect the leading edge of the first article.
 15. Thesystem of claim 1, wherein the sensor is an infrared sensor, aphotoelectric sensor, an optical photo-eye, or a proximity sensor. 16.The system of claim 15, wherein the sensor is disposed parallel to themovable belt of the first picking device.